Process and apparatus for vulcanizing rubber goods.



A. L. ,COMSTOCK. PROCESS AND APPARATUS FOR VULCANIZING RUBB'ER 0000s.

APPLICATION FILED MAY 16.. 1913. V

- 1ate11red.l.)ec. 24,1918.

utented Dec.

3 SHEETSSHEEI 2.

A. L. COMSTOCK.

PROCESS AND APPARATUS FOR VULCANIZING RUBBER GOODS.

APPLICATION FILED MAY 16. 1913. 1,289,043.

A. L. COMSTOCK.

APPARATUS FOR VULCANIZtNG RUBBER GOODS.

APPLICATIOR FILED MAY16,19\3- Rammed Dec 2%,- M18.

3 SHEETSSHEET 3.

.UNIED STATES 3 FFICE. 4

ALLEN L. COMS'IOCK, OF BOSTON, MASSACHUSETTS, ASSIGNOR T0 AMERICAN RUBBER COMPANY, A CORPORATION OF MASSACHUSETTS.-

PROCESS AND APPARATUS FOR VULCANIZING RUBBER GOODS.

To all whom it may concern Be it known that I, ALLEN L. CoMsTocK, a citizen of the United States. a resident of Boston, in the county of Suffolk and State of Massachusetts. have invented certain new .and useful Improvements in Processes and Apparatus for Vulcanizing Rubber Goods, of which the following is a specification.

.My invention relates to processes and ap-' paratus for vulcanizing rubber goods. I will describe a process e'mbodying my invention as well as an apparatus also embodying the same. to wh ich the present proccss and other processes for vulcanizing may be applied. v

In the practice of my process for the vulcanization of rubber goods, I create a desiredvacuum within a vulcanizing oven. and after the desired vacuum is obtained. I introduce into the menu vulcanizing medium. The vulcanizing medium which I prefer is in the form of a gas. ()nepurpose of creating a vacuum in the vulcanizing oven. and afterward introducing the vulcanizing medium. is to insure a better distribution of the vulcanizing medium throughout the oven so that there will be more uniformity of the vulcanizing heat in all parts of theoven. In order to obtain the best results from the use of a vacuum, both as regards obtaining uniformity of heat for vulcanization and the removal of volatile substances' or gases from the rubber goods to be vulcanized. I prefer to heat the vulcanizing oven before creating therein the desired vacuum. The vulcanizing medium is heated to the vulcanizing temperature either before being introduced in the vul'canizing oven or after it has been introduced in the oven or while being introduced in the oven. The vulcanizing medium also may or may not be under pressure. In practice I have. successfully used carbon dioxid gasas a'vulcanizing medium, though it will be understood that I do not limit myself to this gas. as other gases or inert vapors may be used. \Vhen carbon dioXid is employed the use of the vacuumhas the additional function of excluding air from the system and process.

The vulcanizing oven during vulcanizv tion may be at a temperature equal to or above. or below the vulcanization temperaizing oven is above the temperature of the Specification of Letters Patent.

uniformly heated at all points.

In prac- Patented Dec. 245 1918.

Application filed May 16: 1913. SeriaINo. 767,967.

yulcanizing medium, thus eliminating the effect of radiation of heat from the vulcanizing medium.

()ne way of carrying out'my process of vulcanizing rubber goods. such for example as rubber foot-wear, is to heat the vulcan- -izing oven, before or after the rubber goods to be vulcanized are placed within it, and

the oven tightly closed by its door or cover. i In practice I have found-that the best results are obtained when the vulcanizing oven is This uniformity of heat throughout all portions of the vulcanizing oven may be secured by completely surroundingit by a steam jacket. For practical reasons, in the case of a steam jacket. that portion applied to the door or cover of the vulcanizing oven may be formed by a heating coil in the door or cover. I may. however. heat the vulcanizing oven by means of steam coils arranged Within the oven through which steam is circulated 'in any well known way. Preferably. if this form of heating is used. there will be four coils. each coil arranged in a quadrant. and the steam circulation through each quadrant is from the topmost coil downward. The steam jacket about the oven proper and the steam coil are supplied from a source of steam which circulates in the steam jacket and coil. To prevent radiation of heat from the oven. 21 suitable heat insulator, such as asbestos. may be employed.

After the air is extracted by a vacuum 90 apparatus the vulcanizing medium, such as carbon dioxid gas. is then introduced into the vulcanizing oven so asvto completely fill it. Preferabl v.to be sure that only the vulcanizing medium is within the vulca-nizing oven. and for economical rcasonsand the other reasons hereinbeforc stated in carrying out my process, I create a desired vacuum within the vulcanizing oven byaneans of a vacuum pump. In practice I create a vacum of about 28 inches. but lesser vacuums may be employed.

I may state at this point that the heating of the vulcanizii'ig oven to the desired temperature may be obtained \ylillc tlw vulcanizing oven is being exhausted by tliewaciunn pump. Also in the event that the vulcanizingmcdium is raised to the proper vulcii'nizing tempt-mature and prcssurctifthc1nc(liuni=., is to be used under j'n'csslli'cl within the vulcanizing oven. the vulcanizing oven may be raised to its proper temperature during the heating of the gas. It is also Within my vulcanizing oven for the length of time reinvention to have a desired temperature and qulrcd toaccomplish vulcanization of the pressure of the carbon dioxid gas in the rubber goods, its temperature being ma1n-- torage tank. The variations of th s sevtained by the heated vulcanizing oven.

5 eral steps may take place according to cir- After the vulcanization of the rubber 7 cumstances, because in my process the pring'OOClS has been completed, the carbon (llOXid cipal function of the heated insulating oven ga m y e ret rned to the storage tank for is as an insulator to prevent radiation of further 86- heat from the 'vulcanizing mqdium and to Above I have set forth at length the dlf- I hold the vulcamzing'medium at the proper nt teps, of my process and some vari- 7 vulcanizing temperature. ations thereof within the scope of the inven- When the vulcanizi imaium is carbon ion, together with the purposes of the difdi xid gas, it is stored n a suitable st r g ferent steps and their variations. I will tank under pressure, and when in usein the now state, briefly,- one method-oft procedure 15 vulcanizing oven fit attainsja pressure of employed in the vulcanization or goods com- 8 fromBO to 32 pounds. ":T'have'foundit nec-. mer ially.

essary to have a definite relation between The vulcanizlng oven is firstfheated after the pressure and temperature of the gas WhlCh. its (1001' 1S opened t0 il'itIOdllCG the before entering the vulcanizingoven to. obrubber goods. to be vulcanized. This. of

tain precise conditions within the oven. The course, reduces momentarily the tempera- 8 storagetank should be..of..,such capacity as ture of the oven but the oven quickly regains to quantity and pressure that will insure Its lost temperature, which is ralsed to the the proper volume oitgnain.thecven at the 4 deslred pointas qulckly as possible. In the desired pressure and tem 'erature. The decase of vulc'unlzation of boots and shoes I sired pressure of thdzcfil on dioxid gas in employ about6O pounds pressure of steam 9 the vulcanizing' oven 7 may be obtained by in a steam jacket. After the door has been means of a compression pump,.and prefersealed in position, the oven is exhausted to ably by a duplex,- ion pump; that, a yacuumpfabout 27 inches. 5;}

. 30 gradually increase ijhe ssure without in gas is then 1 termittent reductio T the h com the p, i in Operaare subjected to colibtaiit gradually, ;;in tion, an t the prehe When a creasing pressure. --j 'Ihez-heatingyofithe'carpressure of at on diox1d gas. f about 30 bon dioxid gas'may be accom l1shed;in,;any pounds has -Been attained in thiivulcanizing troduced into thiibveh through 9 55 desired way. .One way in w ich this'may oven, the slipply of carbon '"iiibuiid' gas is 1 be done is by a preheater which raises ,the cut off, and i'n a few minutes,',.OWing to the carbon dioxid gas to the vulcaniz'ing tem high temperature of the steam (at about 85 ,perature as it enters the vulcanizing oven. pounds), in the preheater, the carbon dioxid The preheater may assume any desired form, gas attains a temperature at which vulcan- 40 but I prefer to' employ a series of coils, I 'ization commences. In order to shorten the 1 through which the gas flows, inclosed' withtime of vulcanization the carbon dioXid gas in a casing. Steam is eirculatedwithinthe is still further heated by the preheater, and casing at a pressure whichwill heat the caralso by the steam jacket until the proper bon dioxid gas to theidflired iyfllbanizing vulcanization temperature has been reached,

. temperature. 7 Of course, suitable gages are which, for boots and shoes, is about 280 F., 1

provided to indicate pressures? inf-steam and its pressure about 32 pounds. At this wherever required, as well as the pressure point the carbon d-ioxid is confined withof' the carbon dioxid Within the vulcan-- in the vulcanizing oven for theiulcanization iz'in'g. oven, and also a suitable thermometer 'period, which in the case of boots and shoes or thermometers to indicate when. the proper. is about one-and one half hours. When the 1 vulcanizing temperature of th'efl carbon dicarbon dioxidgas has reached atemperature oxid gas has been reached. whilei'iu the, vulof about 280 F. the steam pressure-in. the

canizing oven. In order that gas. uniform steam'jacketof the vulcanizingoven may be temperature of the vulcamzing gas may be, reduced 'to' about 46 pounds, at which point attained by the carbonvdibxidasails-prefer I have-foundlthat there is no loss of tem- 1 t eater for a perature of the carbon dioxid gas during the to circulate it through he pre period of time-,siitu'd o r ;I---. employ a suitable pump, which may he In the a ompanying drawings I have duplex compression pump,.whicri=withdraws shown a pieferr'ed form of apparatus for the gas from the vulcanizing oven at one carrying out the hereinbefore described pro- 1 end and introduces it'into thevulcanizing cess. This apparatus may also be used in oven at the other end, meanwhile passing the other processes for vulcanization. In' the carbon diOXid' gas through the preheater. drawings Figure 1 is a top plan view of an -When the carbon dioxid gas has reached the apparatus embodying my invention. Fig. vulcanizing temperature 1t is confined in the 2 is aside elevation. Fig. 3 is a view in 1 vertical longitudinal section of a vulcanizingoven embodying my invention and applicable to the hereinbetore described process. Fig. -.t is a vertical section taken on the line -lt of Fig. 3, looking in the direction of the arrows. Fig. 5 is a vertical sectional view of a form of pr'eheater.

Similar letters of reference designate corresponding parts in all of the figures.

A designates a VlllOtllllZlIlQ' oven of a suitable construction to withstand pressure both externally and internally, B is a storage tank for a vulcanizing medium such as carbon dioxid gas. C a compression pump preferably of the duplex compression type, and

'which may also act as a vacuum pump, D what 1 term a preheater, and E .a vacuum' pump.

The vulcanizing oven is preferably horizontally arranged. and it has an opening at one endwhich is closed by a swinging door or cover a. from a pivoted bracket (1 so that it may be swung into and out of position. (See Fig. 1). Bolts (not shown) or any other form of fastening may be used to hold the door tightly against the end of the vulcanizing oven. As here shown the vulcanizer is provided with a steam jacket comprising a casing l and a steam coil a in door a. A heat insulator (1 (preferably asbestos) is shown as being provided between the wall of the door a and the steam coil, and I also'preferably inclose the steam jacket a with a heat insulator. This, however, is not illustrated. Steam is supplied to the jacket and coil a from a. steam main a flexible and detachable connection a being employed between the coil (1 and the main a Circulation of steam through the jacketand coil is provided for by the outlets a which discharges into a pine (1. provided with a suitable form of steam trap a". The outlet (1 from the steam coil is a preferably flexible and detachable connection. Other means may be employed to heat the vulcanizing oven, such, for example, as the arrangement of heating pipes within the oven hereinbefore set forth. It will be understood that suitable tracks are provided within thevulcanizing oven for trucks upon which are placed the rubbe goods to be vulcanized.

The storage tank 13 for the carbon dioxid gas may be of any construction, and at least of a capacity hereinbefore set forth, and

may be charged from any source through a valved pine b. The carbon dioxid gas is discharged from the tank B, through pipes 1 and 2. to the compression sideof the pump C, and discharged from the pump through pipes 8, 4, into what I term a preheater (Fig.

5), where it is heated and discharged through pipes 5, G and 7 into the vulcanizing oven at its forward end and at the bottom thereof (see Fig. 4). The heated gas, until it As shown; the door is suspended reaches the preferred vulcanizing temperature is passed through the vulcanizing oven back to the pump ("through the pipes 8, 1 and 2, to be again returned to the vulcanizing oven through the preheater through the path just traced. \Vhen'the carbon dioxid gas has reached its preferred\ulcanizing temperatureit is sealed in theiulcanizing oven by means o1 valves 9 and 10. After the vulcanization o't'the rubber goods. the carbon dioxid gas is returned to the storage tank It through the pipes T. 6, '11, around the vacuum side of pump C by pass 12 and pipe 1 to the storage tank. Of course valves will be provided in the several pipe'connections which will have to be opened and closed to permit'of the fio w ofthe carbon dioxid gas in the manner hereinbefore stated. i

The form ofp reheater D which I have illustrated comprises a casing (Z containing a plurality of coils rlconnecting at both ends with headers (7 Steam is introduced and circulated through the casing 03 in direct contact'with the coils (Z in order to heat the carbon dioxid gas.

- The vacuum pump E may be of any desired construction and it is connected with the interior of the vulcanizing oven through a valved connection 13. i i

Havingthus described my invention, what I desire to claim is: i i

1. A process of vulcanizing which conislsts in removing the atmospher surrounding the goods and subsequently subjecting them to an atmosphere conslsting off a gas substantiallv devoid of free oxygen, said gas having heat applied continuouslythereto to.

' hausting the vulcanizing oven of air, filling the vulcanizing oven with a vulcanizm medium which is substantially devoid of free oxygen, and which is preheated to the vulcanizing temperature.

4. A process for vulcanizing rubber goods which consists in introducing the rubber goods in a 'vulcanizing oven heated to a temperature about the vulcanizing temperature, filling the vul'oanizing oven with a vulcanizing medium and circulating a continuous current of the same 'into and out of the vulcanizing oven until the vulcanizing tem perature isreached, and confining and arresting the current vulcanizing medium within the vulcanizing oven until the required vulcanization is effected.

5. A process for vulcanizing rubber goods which consists in introducing the rubber goods into a vulcanizing oven heated to a temperature about the Vulcanizing temperature, filling the vulcaniziiig oven with a vulcanizing medium and circulatin a continuous current of the same into and out of the vulcanizing oven and a preheater until the vulcani'zin temperatur is reached, and then arresting the current of vulcanizing medium withing the vulcanizingoven until the required vulcanization is effected.

6. A process for vulcanizing rubber goods which consists in introducing the rubber goods into a vulcanizing oven, heating and maintalmn the vulcanizing oven at a temperatur a out that required for the vulcanization, filling the vulcanizing oven with a vulcamzmg medium, andcirculating the medium-into and out of the oven until it reaches its vnlcanizing temperature, and

p then confinin the heated vulcanizing me.

dium within the oven until the required vulcamzation 1s efi'ected, A

r 7. A process for vulcanlzmg rubber goods which consists in -introdu cing the rubber goods into a vulcanizing oven, heating and maintaining the vulcanizing oven at a temperature about that required for vulcanlzation, exhausting the oven of air, filling the vulcanizing oven with a vulcanizing medium,'and circulat ng the medium through the oven and a preheater until itrcaches its vulcanizing temperature.

8. A process for vulcanizing rubber goods which consists in producing a desired vacuam in a heated vulcani'zing oven containing the rubber goods to be vulcanized, and introducing into the oven a vulcanizing medium which is circulated through the vulcanizing oven and through a pressure pump which constantly raises-the pressure without inter mediate reduction.

9. A process for vulcanizing rubber goods which consists in producing a desired vacuum in a heated vulcanizing oven containing the rubber goods to be vulcanized, introducing into the oven avulcaniz'ing medium, and ClIClllililIlg it through the oven and a heater and giving said medium a gradually increasing pressure,

10. A process for vulcanizing rubber goods which consists in producing a desired vacw um ln'a heated vulcanlzlng oven contam- A ing the rubber goods to be vulcanized, in-

troducing into th oven a vulcanizing mc dium, circulating it through the oven and a heater and giving said medium a gradually increasing pressure, and finally confining the same Within the oven during a portion of the vulcanizing period.

. vulcanizing temperature.

11. In an apparatus for vulcanizing ruin her goods, the combination \vitha vulcanizlng oven, means for heating and maintain-' 'preheate'r to have it attain its vulcanizing temperature, and means for confimng the gas within the vulcanizing oven after it has attained a vulcan'lzing temperature.

12, I11 combination, a heated vulcanizing oven, a source of vulcanizing gas, snbstantially devoid of free oxygen, means for cutting off the gas from the source after a determined pressure of gas has been attained in/the oven, and means for preheating the gas as it passes into the vulcanizing oven,

13. In combination, a heated vulcanizing oven, a source of vnlcanizing gas, substantially devoid ofsfrceoxygen, means for cutting off the gas from the source after a dc termined pressure of gas has been attained in the oven, andmeans for preheating the gas as it passes into the vulcanizing oven and for circulating the gas through the oven and heater until the gas has reached its vulcanizing temperature.

It. Incombination, a heated vulcanizing oven, :1 source of vulcanizing gas, substantially devoid of free oxygen, means for cutting off the gas from the source after a determined pressure of gas has been attained in the oven, means for preheating the gasas it passes into the vulcanizing oven, and for circulating the. gas through the oven and heater until the gas has reached its vulcanizing temperature, and means for confining the gas within the vulcanizing oven after it has reached a vulcanizing temperature. p

15. In combination, a heated vulcanizing oven, a source of vulcanizing gas substan tially devoid. of free oxygen connected therewith, means for cutting oil the gas from the oven, a source of vulcanizing gas substan- 1 tially devoid of free oxygen connected therewith, means for cutting off the. gas from the source after a determined pressure of gas has been attained in the vulcanizing oven, a preheater, a compression pump, means for affording a circulation .of the gas by the pump thri'iugh the preheater into the oven at one end and out of the oven at its opposite end, and means for confining the gas in the vulcanizing oven after it has attained a 17 .r In combination, a heated vulcanizing oven, a source of vulcanizing gas substantially devoid of free oxygen for supplying a volume of gas to said oven, a compression pump for gradually increasing the pressure of the volume of gas within the oven and having a connection for circulating the gas Within the oven, anda heater for the gas while it is being circulated by the pump.

18. In combination, a heated vulcanizing oven,- a source of vulcanizing gas substantially devoid of free oxygen for supplying a volume of gas to said oven, a compression pump for gradually increasing the pressure of the volume of gas Within the oven and having a connection for circulating the gas within the oven, a heater for the gas while it stantially devoid of free oxygen, a heater,

and means connected with said source, oven and heater for withdrawing medium'from said source and circulating it through the heater and oven.

20. In a vulcanizing apparatus, a vulcanizing oven, means for heating the oven, means for creating a vacuum in said oven, a

source of supply of vulcanizing medium substantially devoid of free oxygen,a heater for heating the medium and means for drawing the medium from the source and also for circulating it through the oven andheater independently of the said source.

21. In a vulcanizing apparatus, a vulcanizing oven, means for heating the same,

means for producing a vacuum in said oven, at source of supply of vulcanizing medium, a heater for the medium, a circulating system including said oven and heater, and means for drawing the medium from said source and also for circulating it through said sys-- tem until'a desired temperature and pressure of gas is reached in the oven, said means being of a type to gradually increase the pressure in the ovenwithout intermediate reductions of-press'ure.

22. In a vulcanizing apparatus, a vulcanizing foven, means for heating the same, means for producing a vacuum in said oven, asource of supply of vulcanizing medium, a Theater for the medium, a circulating system includingsaid oven and'heater, and a duplex pump for drawing the medium from said source and also for circulating it through the said system until a desired temperature and pressure of medium is pro duced in the oven.

, gradually heating the g .said article to gas under pressure in excess of atmospheric and at a temperature below vulcanizing temperature for compacting the same, and then, while maintaining the said gas at the said pressure, raising the temper-' a'ture of the said gas and vulcanizing the mass so purged and compacted.

24. That improvement in the art of treating rubber, Whichconsists in subjecting the article under treatment to a reduced pressure and a temperature suflicient tovolatilize and dissipate the volatile, gaseous and liquid matter within and upon the mass of said article, thereby facilitating the liberation and escape of'the same from within the said mass, and then immediately thereafter subjecting the said article to the pressure of gas at a temperature below the vulcanizing temperature for compacting the said mass, and then, while maintaining the said ressure constant, vul'canizing the mass so reed from the said components and compacted.

25. The herein-described method which consists, in'placing articles to be vulcanized in a heated vulcaniz ng chamber, closing the chamber, producing a vacuum therein,

breaking the vacuum, forcing heated gas below the vulcanizing'temperature into the chamber, raising the pressure therein, and as to vulcanizing temperature while maintaining the said pressure substantially constant.

2-6. 'Ehe herein-described inethod of vulcanizirfg rubber articles, which consists in placing the articles upon forms, heating the ,vulcan'izingvchamber, placing the articles'in the ,vulcanizing chamberyclosing the chamber, materially reducing the pressure within the chamber, thereby drawing oil the volatile constituents within the articles, and causing them to adhere to the forms, then raising the pressure within the chamber, and compacting the articles and then while maintainlng the said pressure substantially constant heating the interior of the chamber and Vulcanizing the articles. 1

In testimony whereof I hereunto sign my name in the presence of two subscribing witnesses.

ALLEN L. COMSTOCK.

Witnesses: I

' KENNEDY M. THOMPSON, EUGENE W. RUTHERFORD. 

